STTH152RL — a 200 V, 1.5 A fast recovery diode in a DO-15 axial package
The STTH152RL from STMicroelectronics is a standard fast recovery diode rated for 200 V reverse voltage and 1.5 A average forward current, packaged in a DO-204AC (DO-15) axial-lead through-hole case. Its 32 ns reverse recovery time (trr) places it in the fast-recovery class (≤500 ns, >200 mA), making it suitable for high-frequency rectification, freewheeling, and snubbing circuits in power supplies and converters.
32 ns trr — what it means for switching circuits
A 32 ns trr at rated conditions means the diode recovers quickly from forward conduction, reducing switching losses and ringing in circuits operating above 50 kHz. This is a meaningful improvement over standard recovery diodes (trr > 500 ns) and allows the STTH152RL to be used in continuous-conduction-mode boost converters or as a freewheeling diode in flyback topologies without excessive heat buildup.
200 V / 1.5 A — where it fits in the power budget
With a 200 V reverse voltage rating and 1.5 A average forward current, this diode is sized for low-to-medium power rails — think 48 V telecom supplies, 24 V industrial PFC stages, or auxiliary windings in off-line converters. The forward voltage drop is 950 mV max at 1.5 A, which sets the conduction loss floor at about 1.4 W at full load; adequate heatsinking or airflow is needed if the ambient exceeds 85°C.
DO-15 axial package — through-hole assembly considerations
The DO-15 axial package (DO-204AC) is a through-hole form factor with wire leads on 0.300-inch (7.62 mm) centres. It is not compatible with surface-mount reflow processes; boards must be wave-soldered or hand-soldered. For new designs, a surface-mount alternative like the SMB or SMA package would reduce assembly cost, but the axial lead is still common in high-reliability, high-temperature, or retrofit applications where through-hole is preferred for mechanical robustness.
175°C junction temperature — thermal headroom for harsh environments
Rated for a maximum junction temperature of 175°C, the STTH152RL can operate in elevated ambient conditions such as inside a sealed power supply, motor drive enclosure, or lighting ballast where internal temperatures reach 85–105°C. This headroom also allows for higher current derating at lower ambient temperatures without exceeding the junction limit.